Monitoring atmospheric metal pollution: a review of the use of mosses as indicators

This article reviews the literatureon the use of mosses for monitoring atmospheric metalpollution. It discusses the nature of mosses, themechanisms for moss uptake of metals from the air andwet precipitation, the various forms in which mossesare used for this purpose, and cases in which mosseshave been used for monitoring local hot spots ofpollution, and regional patterns of metal pollution.Also highlighted are the questions of uptake of metalsfrom the substrates, interspecies differences, and acomparison of the effectiveness of mosses with otherindicator materials, among other issues.     

Influence of environmental parameters on the accuracy of nitrogen dioxide passive diffusion tubes for ambient measurement

Two studies at three sites in the UK provided confirmation that systematic positive bias in NO2 diffusion tube measurement occurred because of changes to "within-tube" chemistry, rather than eddy diffusion at the mouth of the tube. In the first study in Cambridge, UK, sampler overestimation for 1 and 2 week exposures was compared to corresponding time-averaged monitor measurements (NO-NO2-NOx, O3) and weather variables. Noninearity between sampler and monitor NO2 measurements was interpreted in terms of spatial and temporal variations in relative and absolute availability of NO, NO2 and O3 at the site. A maximum overestimation occurred for an exposure mean NO2/NOx approximately 0.5. The separate contributions of reduced NO2 photolysis and eddy diffusion were compared in Study II using samplers of two materials, acrylic and quartz, and of different lengths (40, 55, 71 and 120 mm) at three sites: Norwich background, Cambridge intermediate, London kerbside. For compared sites, NO2 measured by acrylic samplers was significantly higher than for equivalent quartz samplers. For quartz samplers [NO2]mean was only just above the monitor at Norwich and London; sampler/monitor NO2 = 1.04 (P = 0.59) and 1.01(P = 0.76), respectively. For acrylic samplers the order of [NO2]mean was 40 mm > 120 mm > 71 mm > or = 55 mm. Excepting 40 mm samplers, this accords with a chemical bias where co-diffusing NO and 03 molecules in longer tubes have more time to react to form excess NO2. Bias in 40 mm samplers is discussed. Eddy diffusion is negligible for standard samplers because [NO2]mean was equivalent for 55 mm and 71 mm acrylic samplers and close to monitor NO2 for 71 mm quartz tubes. Both studies showed that sampler accuracy was dependent on location. Significantly, overestimation was greatest (approximately 3-4 ppb) where the NO2 annual mean was approximately 20 ppb, close to the UK and EU air quality standard of 21 ppb.     

Assessing the Effects of Atmospheric Ethylene on Epinasty and Tuber Yield of Potato (Solanum Tuberosum L.) Near Polyethylene Manufacturing Plants

A multi-year programme was performed to assess the effects of atmospheric ethylene on potato (Solanum tuberosum L.) in the vicinity of polyethylene manufacturing plants. There was a strong temporal variation of the hourly ethylene concentrations measured close to the sources from 1982 through 1991. Growing seasonal means exceeded 12 g m^–3 ethylene, the threshold for phytotoxic effects under laboratory conditions. Young test plants of potato showed an epinastic response to enhanced levels of ethylene. This response was reversible and did not occur when atmospheric ethylene was not detected. Based on hourly observations for the growing seasons of 1984 through 1991, epinasty occurred on average during circa 5% of the growing season and varied from circa 1% in 1985 to circa 18% in 1991. At night, ethylene concentrations were higher and epinasty was more frequent than during daylight hours. The intermittent exposures to ethylene did not affect tuber yield for the growing seasons of 1982 through 1990. The occurrence of epinasty indicated that ethylene exposure levels in the vicinity of the industrial sources might be sufficiently high to affect sensitive plants.     

Degradability and Sediment Sorption of an Alcohol Polyglycol Ether Surfactant Putatively Useful for the Control of Red Swamp Crayfish in Rice Fields

This work reports studies of the degradation rates of a fattyalcohol polyglycol ether non-ionic surfactant, Genapol OXD-080, putatively useful for the control of red swamp crayfish (Procambarus clarkii Girard) in rice fields under laboratory and field conditions. The influence of temperature,sediment site specificity and sorption were taken into account.The degradation kinetics of the surfactant depends on the experimental conditions: type of inocula and temperature. Thedistribution of this chemical in aquatic systems was also examined. Genapol OXD-080 was removed into the sedimentsreadily after application, and sorption was considered the majorpath of removal from the water phase. Data suggest that furtherstudies are required regarding the effects of Genapol OXD-080 in aquatic organisms resident in rice fields, in parallelwith the development of technologies related with the use ofsurfactants to control P. clarkii populations.     

Monitoring of Seasonal Vegetables for Pesticide Residues

Market samples (60) of six seasonal vegetables were monitoredduring 1996–1997 to determine the magnitude of pesticidalcontamination. The estimation of insecticide residuesrepresenting four major chemical groups i.e. organochlorine,organophosphorous, synthetic pyrethroid and carbamate, was doneby adopting a multiresidue analytical technique employingGC-ECD and GC-NPD systems with capillary columns. The testedsamples showed 100% contamination with low but measurableamounts of residues. Among the four chemical groups, theorganophosphates were dominant followed by organochlorines,synthetic pyrethroids and carbamates. About 23% of the samplesshowed contamination with organophosphorous compounds abovetheir respective MRL values. More extensive studies coveringdifferent regions of Haryana state are suggested to get a clearidea of the magnitude of vegetable contamination with pesticideresidues.     

Isotopic characterisation of lead deposited 1989-2001 at two upland Scottish locations

The isotopic composition of lead collected with grass samples taken over the period 1989-2001 from plots at two upland locations (Glensaugh in north east and Hartwood in central Scotland) has been determined using thermal ionisation mass spectrometry. Although marked reductions in lead concentrations in grass were observed at Glensaugh in the initial three years, subsequently concentrations have remained relatively constant (1-3 microg g(-1)) in all plots to the present day. The one exception was a roadside plot at Hartwood which showed a large reduction from 1.0 microg g(-1) in 1999 to 0.2 microg g(-1) in 2000 following the abolition of petrol lead in the UK at the beginning of 2000. The total concentrations at this plot were consistently lower than those found at plots away from road traffic but exposed to the prevailing wind direction. The 206Pb/207Pb ratio increased steadily at all the plots throughout the period of the study indicating the reducing influence of petrol lead but the changes were not as great as might be expected with the decrease in the use of leaded petrol. Assuming the collected lead had only two sources, petrol lead and a diffuse background "industrial" lead, the proportion of petrol lead was only in the range 17-69% for roadside samples and 0-39% in other samples. A substantial proportion of deposited lead, therefore, now has its origin other than in petrol. Mixing curves indicate that whereas the lead deposited at Glensaugh could be defined by only two end members, that at Hartwood needs more than two components in the mixture. The results also suggest that although petrol lead has been eliminated, traffic is still a source of lead and another source defined as "traffic lead" should be considered.     

Chromium speciation and fractionation in ground and surface waters in the vicinity of chromite ore processing residue disposal sites

Chromium concentrations of up to 91 mg l(-1) were found by ICP-OES for ground water from nine boreholes at four landfill sites in an area of S.E. Glasgow/S. Lanarkshire where high-lime chromite ore processing residue (COPR) from a local chemical works had been deposited from 1830 to 1968. Surface water concentrations of up to 6.7 mg l(-1) in a local tributary stream fell to 0.11 mg l(-1) in the River Clyde. Two independent techniques of complexation/colorimetry and speciated isotope dilution mass spectrometry (SIDMS) showed that Cr was predominantly (>90%) in hexavalent form (CrVI) as CrO4(2-), as anticipated at the high pH (7.5-12.5) of the sites. Some differences between the implied and directly determined concentrations of dissolved CrIII, however, appeared related to the total organic carbon (TOC) content. This was most significant for the ground water from one borehole that had the highest TOC concentration of 300 mg l(-1) and at which < 3% of Cr was in the form of CrVI. Subsequent ultrafiltration produced significant decreases in Cr concentration with decreasing size fractions, e.g. <0.45 microm, < 100 kDa, <30 kDa and < 1 kDa by the tangential-flow method. As this appeared related more to concentrations of humic substances than of TOC per se, horizontal bed gel electrophoresis of freeze-dried ultrafilter retentates was carried out to further characterise the CrIII-organic complex. This showed for the main Cr-containing fraction, 100 kDa-0.45 microm, that the Cr was associated with a dark brown band characteristic of organic (humic) matter. Comparison of gel electrophoresis and FTIR results for ultrafilter retentates of ground water from this borehole with those for a borehole at another site where CrVI predominated suggested the influence of carboxylate groups, both in reducing CrVI and in forming soluble CrIII-humic complexes. The implications of this for remediation strategies (especially those based on the addition of organic matter) designed to reduce highly mobile and carcinogenic Cr(VI)O4(2-) to the much less harmful CrIII as insoluble Cr(OH)3 are discussed.     

Distribution of Chlorinated Organic Pollutants in Harbor Sediments of Livorno (Italy): A Multivariate Approach to Evaluate Dredging Sediments

Dredging is a very important procedure for harbor management. InItaly the guidelines for the offshore dumping of dredged materials are issued by the Ministry of Environment. Theydescribed a few steps of dredging activities, such as thesampling strategy, but do not deal with limits or guide-valuesfor the chemical, physical and biological composition of theresulting sediments. The quality of dredged materials is mainlydependent on the presence of inorganic and organic pollutants.In particular, polychlorinated biphenyls (PCBs) and organo-chlorinated pesticides are seen as a high priority inmarine environment by international organizations because oftheir persistence, toxicity and bioaccumulation capacity.In this article the presence of some PCBs and organo-chlorinatedpesticides in sediment samples collected from the harbor ofLivorno (Northern Tyrrhenian Sea) was investigated. Theconcentration of HCHs, Aldrin, Chlordanes, DDEs, DDTs, and PCBsin 12 representative sites ranged between <1 g kg^–1and 95, 19, 32, 35, 107, and 111 g kg^–1, respectively.The application of univariate and multivariate statisticaltechniques, such as linear regression analysis and principalcomponent analysis, to the experimental data showed a differentdistribution of PCBs in the two sediment layers. On thecontrary, the vertical distribution of the other investigatedpollutants was more homogeneous and affected by randomvariability. The multivariate approach was an important tool to establish more rational criteria for the management of dredged materials.     

Application of intrawell testing of RCRA groundwater monitoring data when no upgradient well exists

A statistical quality control approachto detect changes in groundwater quality from aregulated waste unit is described. The approachapplies the combined Shewhart-CUSUM control chartmethodology for intrawell comparison of analyteconcentrations over time and does not require anupgradient well. A case study from the U.S.Department of Energy's Hanford Site is used forillustration purposes. This method is broadlyapplicable in groundwater monitoring programs wherethere is no clearly defined upgradient location, thegroundwater flow rate is exceptionally slow, or wherea high degree of spatial variability exists inparameter concentrations. This study also indicatesthat the use of the Data Quality Objectives (DQO)process can assist in designing an efficient andcost-effective groundwater monitoring plan to achievethe optimum goal of both low false positive and lowfalse negative rates (high power).     

A Watershed-based Cumulative Risk Impact Analysis: Environmental Vulnerability and Impact Criteria

Swine Concentrated Animal Feeding Operations (CAFOs) have received much attention in recent years. As a result, a watershed-based screening tool, the Cumulative Risk Index Analysis (CRIA), was developed to assess the cumulative impacts of multiple CAFO facilities in a watershedsubunit. The CRIA formula calculates an index number based on: 1) the area of one or more facilities compared to the area of the watershed subunit, 2) the average of the environmental vulnerability criteria, and 3) the average of the industry-specific impact criteria. Each vulnerability or impact criterion is ranked on a 1 to 5 scale, with a low rank indicating low environmental vulnerability or impact and a high rank indicating high environmental vulnerability or impact. The individual criterion ranks, as well as the total CRIA score, can be used to focus the environmental analysis and facilitate discussions with industry, public, and other stakeholders in the Agency decision-making process.